This invention relates to semiconductor devices, and particularly to the assembly and packaging of such devices.
Semiconductor devices, e.g., power devices, typically comprise a semiconductor chip disposed within a package and connectors for connecting electrodes on the surface of the chip to terminal leads extending from the package.
U.S. Pat. No. 5,028,987 shows one example of a prior art device of a type with which the present invention has utility; the subject matter of this patent being incorporated herein by reference.
In this patent, the package comprises a cup-shaped base to the inside bottom of which is bonded a semiconductor chip; an apertured, ceramic lid bonded to the side wall of the base; and terminal leads bonded to electrodes on the chip and extending from the chip directly through the lid apertures and serving as the device terminals.
In my co-pending patent application, Ser. No. 823,343, filed Jan. 21, 1992, entitled "Semiconductor Devices and Methods of Assembly Thereof", now U.S. Pat. No. 5,248,901 issued Sep. 28, 1993, there is disclosed, among other things, a device similar to the one disclosed in the patent but wherein, in place of the terminal leads bonded to the chip electrodes, thin metal foils bonded to the interior surface of the ceramic lid are used. The metal foils underlie and seal the bottom openings of the lid apertures, and the metal foils overlie and are directly bonded to the chip electrodes. External electrical connections to the device electrodes are by means of terminal leads which extend into the apertures and into electrical contract with the foils thereunder. The device thus comprises a chip tightly sandwiched between the base bottom wall and the lid inner surface, and has the features of great strength, small size, and high thermal conductivity paths for removing heat from both the upper and lower surfaces of the package.
The present invention provides still further improvements in devices of the type described.